Seat restraint tensioner

ABSTRACT

A seat restraint tensioner for a seat restraint system in a vehicle includes a housing for operative connection to vehicle structure and a movable piston disposed in the housing. The seat restraint tensioner also includes a gas generator operatively connected to the housing for expelling a gas to move the piston. The seat restraint tensioner further includes a plate member interconnecting the housing and a buckle assembly of the seat restraint system for pulling-down the buckle assembly of the seat restraint system in a linear manner.

TECHNICAL FIELD

[0001] The present invention relates generally to seat restraint systems for vehicles and, more particularly, to a seat restraint tensioner for a seat restraint system in a vehicle.

BACKGROUND OF THE INVENTION

[0002] It is known to provide a seat restraint system such as a seat belt in a vehicle to restrain an occupant in a seat of the vehicle. In some vehicles, the seat restraint system may be a lap belt, a shoulder belt or both. Typically, the lap belt and shoulder belt are connected together at one end. The seat restraint system includes a latch plate at the connected end. The seat restraint system also includes a buckle connected at one end by webbing or the like to vehicle structure. The buckle receives the latch plate to be buckled together. When the buckle and latch plate are buckled together, the seat restraint system restrains movement of the occupant to help protect the occupant during a collision.

[0003] It is also known to provide a seat belt tensioner in the seat restraint system for tensioning an occupant belt restraint in the event of sudden vehicle deceleration. An example of such a seat belt tensioner is disclosed in U.S. Pat. No. 5,492,368 to Pywell. In this patent, the seat belt tensioner has a housing with a piston slidably mounted therein and a seat belt reel attached to a shaft of the piston. The seat belt tensioner is operated by pushing a piston with pyrotechnically generated gas and mechanically translating that force into seat belt reeling to wind the belt and produce seat belt tensioning. However, obtaining sufficient rotary action to take up a relatively large amount of webbing of the belt is difficult and inefficient. Also, these seat belt tensioners have a relative thick profile package.

[0004] It is desirable to provide a seat restraint tensioner for a buckle assembly of a seat restraint system of a vehicle. It is also desirable to provide a seat restraint tensioner with linear travel for a seat restraint system of a vehicle. It is further desirable to provide a seat restraint tensioner having few parts to directly remove “slack” in a lap belt area of a seat restraint system in a vehicle. It is still further desirable to provide a seat restraint tensioner for a seat restraint system in a vehicle that is less costly and has a thinner profile package.

SUMMARY OF THE INVENTION

[0005] It is, therefore, one object of the present invention to provide a seat restraint tensioner for a seat restraint system in a vehicle.

[0006] It is another object of the present invention to provide a seat restraint tensioner for a seat restraint system in a vehicle that actuates in a linear manner.

[0007] To achieve the foregoing objects, the present invention is a seat restraint tensioner for a seat restraint system in a vehicle including a housing for operative connection to vehicle structure and a movable piston disposed in the housing. The seat restraint tensioner also includes a gas generator operatively connected to the housing for expelling a gas to move the piston. The seat restraint tensioner further includes a plate member interconnecting the housing and a buckle assembly of the seat restraint system for pulling-down the buckle assembly of the seat restraint system in a linear manner.

[0008] One advantage of the present invention is that a new seat restraint tensioner is provided for a seat restraint system in a vehicle. Another advantage of the present invention is that the seat restraint tensioner is of a linear type to pull-down a buckle assembly of the seat restraint system to restraint an occupant in the vehicle. Yet another advantage of the present invention is that the seat restraint tensioner is more efficient and directly removes slack in the lap restraint area of the seat restraint system. Still another advantage of the present invention is that the seat restraint tensioner has a locking device located farther upstream closer to the buckle assembly and, therefore, can concentrate high load requirements on fewer parts. A further advantage of the present invention is that the seat restraint tensioner has a relatively low cost, fewer parts, is simple and easy to manufacture, and thin profile packaging than current rotary pretensioners.

[0009] Other objects, features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is an elevational view of a seat restraint tensioner, according to the present invention, illustrated in operational relationship with a seat restraint system of a vehicle.

[0011]FIG. 2 is an enlarged fragmentary side elevational view of the seat restraint tensioner of FIG. 1 illustrating a first operative position.

[0012]FIG. 3 is a view similar to FIG. 2 of the seat restraint tensioner illustrating a second operative position.

[0013]FIG. 4 is a sectional view taken along line 4-4 of FIG. 2.

[0014]FIG. 5 is a sectional view taken along line 5-5 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] Referring to the drawings and in particular FIG. 1, one embodiment of a seat restraint tensioner 10, according to the present invention, is shown for a seat restraint system, generally indicated at 12, in a vehicle (partially shown), generally indicated at 14. The vehicle 14 includes a vehicle body 16 and a seat 18 mounted by suitable means to vehicle structure 20 such as a floorpan in an occupant compartment 22 of the vehicle body 16. In this embodiment, the seat 18 is a front seat of the vehicle 14. It should be appreciated that the seat 18 could be a rear, second row or third row seat for the vehicle 14.

[0016] The vehicle 14 includes the seat restraint system 12 for restraining an occupant (not shown) in the seat 18. The seat restraint system 12 includes a latch tongue or plate 23 connected to an end of either one of a lap belt 24, shoulder belt 26, or both. In this embodiment, the shoulder belt 26 has another end connected to a seat belt retractor (not shown). The other end of the lap belt 24 is connected by suitable means such as an anchor plate (not shown) to the vehicle structure 20 or the seat 18. The seat restraint system 12 also includes a buckle assembly 28 connected to the seat restraint tensioner 10 to be described. The latch plate 23 is engageable and disengageable with the buckle assembly 28 as is known in the art. It should be appreciated that, in a preferred embodiment, the seat restraint tensioner 10 is mounted to an inboard side of the seat 18 and the buckle assembly 28 extends above a seat cushion of the seat 18 and the seat restraint tensioner 10 extends toward a front of the vehicle 14. It should also be appreciated that, except for the seat restraint tensioner 10, the seat restraint system 12 and vehicle 14 are conventional and known in the art.

[0017] Referring to FIGS. 1 through 5, the seat restraint tensioner 10, according to the present invention, includes a bracket or base plate 34 connected to the vehicle structure 20 or seat 18 by suitable means such as an anchor bolt 35. The base plate 34 is made of a metal material such as high strength steel. The base plate 34 includes an upper portion formed by a generally planar base wall 36 and a pair of side walls 37 extending generally perpendicular thereto to form a channel 37 a. The base plate 34 has a flange 38 extending inwardly and generally perpendicular to each of the side walls 37. The side walls 37 include a recess or slot 39 extending therein for a function to be described.

[0018] The seat restraint tensioner 10 also includes a housing 40 secured to a lower portion of the base plate 34 by suitable means such as fasteners 41. The housing 40 has a first or piston portion 42 extending longitudinally and a second or gas generation portion 44 extending generally perpendicularly from the piston portion 42 at a rearward end thereof. The piston portion 42 and gas generation portion 44 are generally tubular in shape with a generally circular cross-sectional shape. The housing 40 also includes a piston tube 46 extending longitudinally from the piston portion 42. The piston tube 46 is generally tubular in shape with a generally circular cross-sectional shape. The piston tube 46 has a first open end 48 and a second open end 50 secured to the piston portion 42 of the housing 40 by suitable means such as threads 51. The housing 40 is made of a metal material such as a zinc die-cast material. The piston tube 46 is made of a metal material such as steel or aluminum.

[0019] The seat restraint tensioner 10 includes a piston 52 disposed in the piston tube 46 of the housing 40. The piston 52 is generally cylindrical in shape for sliding movement in the piston tube 46. The piston 52 has an annular groove 54 and a seal 56 such as an O-ring disposed in the annular groove 54 to form a seal with an interior surface of the piston tube 46 to prevent gases from escaping past the piston 52. The piston 52 also has a passageway 58 extending therethrough for a function to be described. The piston 52 is made of a metal material such as steel.

[0020] The seat restraint tensioner 10 includes a plate member 60 interconnecting the buckle assembly 28 and base plate 34. The plate member 60 extends longitudinally and is generally planar and rectangular in shape. The plate member 60 has a neck portion 61 at an upper end thereof disposed between a pair of opposed flanges 62 of the buckle assembly 28 and a head portion 64 extending outwardly from the neck portion 61. The head portion 64 is connected to the buckle assembly 28 by suitable means such as a fastener 66. The plate member 60 also has a plurality of apertures 68 spaced longitudinally therealong. The apertures 68 are generally rectangular in shape and spaced generally evenly apart for a function to be described. The plate member 60 has a lower end disposed in the channel 37 a between the base wall 36 and flanges 38 of the upper portion of the base plate 34 for a function to be described. The plate member 60 is made of a metal material such as high strength steel.

[0021] The seat restraint tensioner 10 includes a locking device such as a retainer clip 70 to prevent the buckle assembly 28 from being pushed down during “normal” usage. The retainer clip 70 is generally planar and rectangular in shape. The retainer clip 70 has a pair of arms 72 spaced laterally and extending downwardly and a flange 74 extending laterally inwardly and generally perpendicular thereto at a lower end of the arms 72. The arms 72 are disposed over the side walls 37 of the upper portion of the base plate 34 and the flanges 74 are disposed in the slots 39. The retainer clip 70 also has a recess 76 extending therein for a function to be described. The retainer clip 70 also has a flange 77 a extending generally perpendicular thereto and an integral pin 77 b extending generally perpendicular to the flange 77 a to hold a cable 104 to be described at an angle relative to an axis of the plate member 60. The pin 77 b is of a breakaway type. The retainer clip 70 also has a cam surface 78 interfacing with the cable 104 after the pin 77 b breaks away to cause an upward rotation of the retainer clip 70 as the cable 104 is pulled in a manner to be described. The retainer clip 70 is made of a plastic material. It should be appreciated that the arms 72 of the retainer clip 70 flex to allow the flanges 74 to snap into the slots 39. It should also be appreciated that the retainer clip 70 blocks the downward travel of the plate member 60.

[0022] The seat restraint tensioner 10 includes a locking device such as a pawl 79 cooperating with the plate member 60 to prevent reverse travel of the buckle assembly 28. The pawl 79 is disposed between the base plate 34 and the plate member 60. The pawl 79 extends longitudinally and is generally rectangular in shape. The pawl 79 has a locking portion 80 extending outwardly to be disposed in the apertures 68 of the plate member 60. The locking portion 80 is generally rectangular in shape and is of a size to fit in the apertures 68. The pawl 79 is made of a metal material such as high strength steel.

[0023] The seat restraint tensioner 10 also includes a spring 82 disposed between the pawl 79 and the base plate 34 to urge the locking portion 80 to be disposed in the apertures 68 of the plate member 60. The spring 82 extends longitudinally and is generally planar and rectangular in shape. The spring 82 has a support portion 84 at one end disposed between the locking portion 80 and the base plate 34 with a generally triangular cross-sectional shape. The spring 82 has a connecting portion 86 at the other end thereof disposed about the end of the pawl 79 and having a general “C” shape. The spring 82 also has an attachment portion 88 extending generally perpendicular thereto and spaced between the support portion 84 and the connecting portion 86. The attachment portion 88 extends through an aperture 90 in the base plate 34. The spring 82 is made of a metal material such as spring steel.

[0024] The seat restraint tensioner 10 also includes a gas generator 94 disposed in the gas generation portion 44 of the housing 40. The gas generator 94 is a pyrotechnic device similar to that used for inflators in inflatable restraint systems to expel a gas into the housing 40. The gas generator 94 includes an electrical connector 96 connected to a source of power (not shown) for activating the pyrotechnic device to expel the gas. The gas generator 94 extends through an aperture 98 in the gas generation portion 44 of the housing 40 and is retained therein by a flange 100 at the end of the gas generation portion 44. It should be appreciated that the gas expelled by the pyrotechnic device of the gas generator 94 will move the piston 52 longitudinally in the piston tube 46 of the housing 40 as illustrated in FIG. 3. It should also be appreciated that the gas generator 94 may be a stored compressed gas used with an electrical trigger in place of a pyrotechnic device.

[0025] The seat restraint tensioner 10 includes a pin 102 extending between the flanges 62 of the buckle assembly 28. The seat restraint tensioner 10 also includes a bushing 105 disposed about the pin 102 between the flanges 62. The seat restraint tensioner 10 includes a cable 104 having one end forming a loop 106 disposed about the pin 102 between one end of the bushing 105 and one of the flanges 62 and fastened to itself by a cable fitting 108. The cable 104 extends along the plate 60 and through the recess 76 of the retainer clip 70. The cable 104 extends around the pin 77 b of the retainer clip 70 and the anchor bolt 35 and is disposed between the base plate 34 and a shoulder washer 110 of the anchor bolt 35. The cable 104 extends through an aperture 112 in the housing 40 and the passageway 56 of the piston 52. The end of the cable 104 is retained by a plug member 114 disposed on the other side of the piston 52. The cable 104 is made of a metal material such as steel.

[0026] In operation of the seat restraint tensioner 10, an occupant (not shown) grasps the latch plate 23 and pulls on the lap belt 24 and shoulder belt 26. The shoulder belt 26 is unwound by the occupant from the retractor. The occupant engages the latch plate 23 with the buckle assembly 28 to restrain the occupant in the seat 18. The seat restraint tensioner 10 is in an initial or first operative position as illustrated in FIGS. 1 and 2. In this position, the retainer clip 70 prevents downward travel of the plate member 60 and buckle assembly 28 during normal usage.

[0027] When the vehicle 14 experiences a collision-indicating condition of at least a predetermined threshold level, an electrical signal is sent to the gas generator 94. The gas generator 94 is activated and a gas is expelled by the pyrotechnic device into the gas generation portion 44 of the housing 40. It should be appreciated that the gas is generated very quickly and completely before the piston 52 moves. The force of the gas against the piston 52 causes the piston 52 to move longitudinally in the piston tube 46 toward the open end 48, pulling on the cable 104, in turn, pulling on the buckle assembly 28 and plate 60. The cable 104 breaks the pin 77 b away from the retainer clip 70 and engages the cam surface 78. The cam surface 78 interfacing with the cable 104 causes an upward rotation of the retainer clip 70 as the cable 104 is pulled by the piston 52. As the piston 52 moves further longitudinally, the plate member 60 and the buckle assembly 28 are pulled downward in a linear manner toward the base plate 34 to take up slack in the seat restraint system 12 and secure the occupant in the seat 18 as illustrated in FIG. 3. The flanges 38 of the base plate 34 guide the movement of the plate member 60 and the locking portion 80 of the pawl 79 is biased by the spring 82 to mate with and pass through one of the apertures 68 in the plate member 60 to provide a locking condition to prevent the plate member 60 and buckle assembly 28 from reversing as the occupant loads the lap belt 24 during the collision. It should be appreciated that the pawl 79 is deflected toward the base plate 34 via the spring 82 as the plate member 60 moves downwardly and returns to mate with and pass through one of the apertures 68 in the plate member 60 via the spring 82 when the plate member 60 stops its downward travel. It should also be appreciated that the force of the gas is mechanically transferred to the plate member 60 by pulling on the cable 104. It should further be appreciated that the seat restraint tensioner 10 may be used for either a rollover condition or a frontal impact condition.

[0028] The present invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation.

[0029] Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described. 

1. A seat restraint tensioner for a seat restraint system in a vehicle comprising: a housing for operative connection to vehicle structure; a movable piston disposed in said housing; a gas generator operatively connected to said housing for expelling a gas to move said piston; and a plate member interconnecting the housing and a buckle assembly of the seat restraint system for pulling-down the buckle assembly of the seat restraint system in a linear manner.
 2. A seat restraint tensioner as set forth in claim 1 including a base plate connected to said housing and for operative connection to vehicle structure and said plate member.
 3. A seat restraint tensioner as set forth in claim 2 including an anchor bolt extending through said base plate for connection to the vehicle structure.
 4. A seat restraint tensioner as set forth in claim 1 including at least one cable having one end operatively connected to said piston and another end operatively connected to said plate member.
 5. A seat restraint tensioner as set forth in claim 4 including a locking device connected to said base plate to prevent downward travel of the buckle assembly during normal usage.
 6. A seat restraint tensioner as set forth in claim 5 wherein said locking device comprises a retainer clip having a recess with a cam surface to interfacing with said cable to cause upward rotation of said retainer clip as said cable is pulled.
 7. A seat restraint tensioner as set forth in claim 5 wherein said locking device comprises a retainer clip having an integral pin to hold said cable at an angle relative to a longitudinal axis of said plate member.
 8. A seat restraint tensioner as set forth in claim 1 wherein said piston includes an annular groove therein.
 9. A seat restraint tensioner as set forth in claim 8 including a seal disposed in said groove to prevent gases from exiting past said piston.
 10. A seat restraint tensioner as set forth in claim 1 including a locking device to prevent reverse travel of the buckle assembly.
 11. A seat restraint tensioner as set forth in claim 10 wherein said locking device includes said plate member having a plurality of apertures spaced therealong and a pawl mating with and passing through one of said apertures to provide a locking condition.
 12. A seat restraint tensioner as set forth in claim 11 wherein said locking device includes a spring to urge said pawl into engagement with said apertures.
 13. A seat restraint tensioner as set forth in claim 1 wherein said housing comprises a piston portion extending longitudinally and a gas generation portion extending perpendicular from said piston portion.
 14. A seat restraint tensioner as set forth in claim 1 wherein said gas generator comprises a pyrotechnic device to expel a gas.
 15. A seat restraint tensioner for a seat restraint system in a vehicle comprising: a base plate for operative connection to vehicle structure; a housing connected to said base plate; a movable piston disposed in said housing; a plate member interconnecting the housing and a buckle assembly of the seat restraint system; at least one cable having one end operatively connected to said plate member and another end operatively connected to said piston; and a gas generator operatively connected to said housing for expelling a gas to move said piston and linearly pull-down said plate member toward said base plate.
 16. A seat restraint tensioner as set forth in claim 15 wherein said housing comprises a piston portion extending longitudinally and a gas generation portion extending perpendicular from said piston portion.
 17. A seat restraint tensioner as set forth in claim 16 wherein said gas generator comprises a pyrotechnic device connected to said housing to expel a gas in said gas generation portion.
 18. A seat restraint tensioner as set forth in claim 15 wherein said piston includes an annular groove therein.
 19. A seat restraint tensioner as set forth in claim 18 including a seal disposed in said groove to prevent gases from exiting past said piston.
 20. A seat restraint tensioner as set forth in claim 15 wherein said piston includes a passageway extending axially therethrough, said cable extending through said passageway.
 21. A seat restraint tensioner as set forth in claim 15 including a locking device connected to said base plate to prevent downward travel of the buckle assembly during normal usage.
 22. A seat restraint tensioner as set forth in claim 20 wherein said locking device comprises a retainer clip having a recess with a cam surface to interfacing with said cable to cause upward rotation of said retainer clip as said cable is pulled.
 23. A seat restraint tensioner as set forth in claim 21 wherein said locking device comprises a retainer clip having an integral pin to hold said cable at an angle relative to a longitudinal axis of said plate member.
 24. A seat restraint tensioner as set forth in claim 15 including a locking device to prevent reverse travel of the buckle assembly.
 25. A seat restraint tensioner as set forth in claim 24 wherein said locking device includes said plate member having a plurality of apertures spaced therealong and a pawl mating with and passing through one of said apertures to provide a locking condition.
 26. A seat restraint tensioner as set forth in claim 25 wherein said locking device includes a spring to urge said pawl into engagement with said apertures.
 27. A seat restraint system for a vehicle comprising: a plate member having a first end for connection to a buckle and a second end; a base plate operatively connected to said second end of said plate member; an anchor bolt extending through said base plate for connection to vehicle structure of the vehicle; a housing connected to said base plate; a movable piston disposed in said housing; a cable operatively connected to said plate member and operatively connected to said piston; and a gas generator operatively connected to said housing for expelling a gas to move said piston and linearly pull-down said plate member toward said base plate.
 28. A seat restraint tensioner as set forth in claim 27 including a first locking device connected to said base plate to prevent downward travel of the buckle assembly during normal usage.
 29. A seat restraint tensioner as set forth in claim 28 including a second locking device to prevent reverse travel of the buckle assembly. 